Measurement of Born Cross Section for $e^{+}{e}^{-}\to K_S^0\bar{\hat{I}}{ž}^{+}\hat{I}{\pounds }^{-}+c.c.$ at $\sqrt{s}=3.51-4.95$ GeV

Abstract

Using $e^{+}{e}^{-}$ collision data collected with the BESIII detector at the BEPCII collider corresponding to a total integrated luminosity of 44~fb${}^{-1}$, we present the first measurement of the Born cross sections for the process $e^{+}{e}^{-}\to K_S^0\bar{\hat{I}}{ž}^{+}\hat{I}{\pounds }^{-}+c.c.$ at 56 center-of-mass energies from 3.510 to 4.951~GeV. By fitting the dressed cross sections of $e^{+}{e}^{-}\to K_S^0\bar{\hat{I}}{ž}^{+}\hat{I}{\pounds }^{-}+c.c.$ with the assumption of a power-law function plus a charmonium(-like) resonance, i.e. $\ddot{I}ˆ(3770)$, $\ddot{I}ˆ(4040)$, $\ddot{I}ˆ(4160)$, $Y(4230)$, $Y(4360)$, $\ddot{I}ˆ(4415)$, {\it Y}(4500), $Y(4660)$, and {\it Y}(4710), no significant signal of any charmonium(-like) state decaying into the $K_S^0\bar{\hat{I}}{ž}^{+}\hat{I}{\pounds }^{-}+c.c.$ is observed. Upper limits on the product of the electronic width and branching fraction at the 90\% confidence level are given for each resonance. Combining this result with the previous measurement of the isospin-symmetric process $e^{+}{e}^{-}\to K^{-}\bar{\hat{I}}{ž}^{+}\hat{I}{\pounds }^0+c.c.$, the ratio of the Born cross sections, $R=\ddot{I}{ƒ}^B(e^{+}{e}^{-}\to K_S^0\bar{\hat{I}}{ž}^{+}\hat{I}{\pounds }^{-}+c.c.)/$$\ddot{I}{ƒ}^B(e^{+}{e}^{-}\to K^{-}\bar{\hat{I}}{ž}^{+}\hat{I}{\pounds }^0+c.c.)$, is found to be approximately 1.

11 Pages, 3 Figures, 1 Appendix, etc